Method of treating pectin



Patented Mn. 1, 1938 Corona, Calii'.,

.zi aju q UNITED STATES PATENT oFlncs- METHOD OF TBEATIhlG PEC'I'IN Gordon Manley Cole and Raymond Edward Cox,

asaignorato California Fruit Growers Exchange, Los Angcles, Calit, a .COI':

poration of California No Drawing. Application February 18,1935, Serial No. 1,075 v This invention relates to a method of treating pectin sols whereby certain fundamental and inacteristics, although these characteristics may differ for different trades and uses; that is to say, certain users require pectin with a uniformly slow setting rate, whereas, a pectin with a fast setting rate is required by others. been dimcult, if not impossible, for the pectin manufacturer to manufacture pectin with a predetermined and uniform setting time or rate. Different source material and extraction methods produce pectins.with differing and generally uncontrollable setting characteristics. .There is, therefore a distinct need for some method where by the setting time or setting rate of pectin can be controlled or modified.

This invention is based upon the discovery that it is possible to alter, at will, one of the inherent, intrinsic and fundamental characteristics of pectin, namely, its setting time, or its inherent ability to cause gelation to proceed in a jelly batch at a certain definite rate. By the method and means of this invention, the setting time of any previously extracted pectin may be changed in the desired direction.

The setting time as used in this specification and in the appended claims means that interval of time which elapses between the instant all the ingredients of the jelly batch, consisting of standard proportions of sugar, pectin, acid, and

total solids, are placed in the final container, af-

ter cooking, and that instant at which gelation of the whole into a coherent mass may be ob-.

' quently be formed from such treated pectin.

Heretofore, it has Honor the pectin is proceeding. An organic acid illustrates a desirable treating agent.

Accordingly, an object oi this invention is to disclose and provide methods and means 'ofchanging or altering the setting time of pectins in sol form.

Another object of this invention is to disclose and provide methods and means whereby it is possible to alter the setting time characteristics of pectins in sol form to any desired and definite, predetermined time.

A further object of this invention is to disclose and provide methods and means of treating pectin sols of various degrees of purity. for the purpose of changing the inherent setting time characteristics, and in particular to retard the setting rate or lengthen the setting time.

Another object of this invention is to disclose and provide methods and means of treating pectin sols with an acidic reagent whereby the setting time may be retarded or speeded up to any desired and predetermined time.

The objects and advantages of this invention will be apparent from a description of-a preferred process and product embodied in the invention and will present themselves to those skilled in the art in the contemplation and use of the invention.

It is to be understood that this invention is directed to the treatment of pectin in sol form, and particularly to the treatment of a pectin which has been previously extracted from a cellulosic source material. Various methods of extraction are known and need not be described herein. In such previously known methods, the pectin is precipitated from the extracts with alcohol, by salting out, or by the so-called aluminum precipitation process disclosed in Patent No. 1,497,884.

It has been determined that the process of this invention is applicable to pectins extracted from' any source, such as, for example, citrus peel, apple pomace, etc. Moreover, the process does not appear to be influenced by the method of extraction, precipitation, or purification used prior to the application of the process of this invention. The sol, being treated in accordance with this invention, may be either of a technical quality or of a more extensively purified quality.

In the following descriptions the process is il-' lustrated as applied to the treatment, in sol form, of commercial pectins having a setting time of about 9 seconds, and to the treatment of pectin in sol for-m obtained from the HCl extraction 0! citrus pulp at a pH of about,l.6. We desire it to be understood that the treatments described are given as illustrations of the invention and the invention is not to be limited to the examples given, but the treatment may be modified in various manners depending upon how the pectin sols are formed, whether by original extraction of the pectin from raw materials, or by redispersing pectin which has previously been precipitated from extraction liquors. The pectin to be treated may be purified by known means.

Again, we desire it to be understood that this invention relates to and is applicable to pectin in sol form extracted from any source, such as, for example, apple pomace, citrus peel, etc. Furthermore, this process does not seem to be influenced by the method of extraction, or purincation of the pectin, that is, whether it be a relatively pure sol made by dispersing a highly purified pectin, or a sol containing appreciable amounts of extractionimpurities.

-As has been stated hereinbefore, the method of the invention contemplates acting upon a pectin sol with a treating agent, so as to alter the inherent time-.of set of the pectin therein contained. The preferred process is carried out" by adding a suitable acid to the pectin sol, and in order to illustrate the process and the results to be obtained thereby, the following examples are given.

62.5 grams of a 160 grade commercial powdered pectin having a setting time of about 9 seconds were dispersed in 5 kg. of 1.16 normal HCl, yielding a 1%% P ctin sol having a pH 01 approximately 0.1, as measured by using a quinhydrone electrode in conjunction with a standard calomel half-cell, standardized against a standard builer solution. 400 cc. portions of this sol were taken from the main supply at intervals shown in Table I, the main supply being held at room temperature throughout the experiment. The treatment of the pectin sol, after removal from the main supply, consisted of precipitation of the pectin from the sol with an equal volume of alcohol, straining the pectin therefrom, adding it to 400 cc. of 50% alcohol, straining and repeating the rinse twicemore. pectin was air dried, thence ground to 65 mesh and standard jellies of satisfactory texture were made.

A "standard Jelly as herein used is composed of approximately 65% sugar solids, plus 2 cc. ofstandard preservers acid pound crystalline tartaric acid't'o 1 pint of distilled water) per ml. volume of finished Jelly, and suflicient pectin to set the whole into a jelly of suitable texture and resiliency. Y

Comparative jelly, grades of various pectins are usually calculated on an ash and moisture free basis. The comparison of the various Jelly grades is thereby on an equal basis, namely, a basis wherein the entire pectin is considered as though pure pectin, entirely free from ash and moisture.

Tam I 154% p ctin sol acidified with H01 to a pH of approximately 0.1 stored at room temperature w g? Time 0! set J'elly grade (Mu trutnlenl all and moisture {no basis) 1 hour 9 sec. 4 hours 92 sec. 179' 21 hours 95 sec. 178 hours 11 min 202 2 days I 28 min 217 8 days 25 min 2% 5 days 23 min M5 9 days (5) min 2ll=g5 'J'elly had set when examined after 5 minutes.

The resulting creased along withretardation, for, as will be noted from Table I,- the jelly grade values (on an ash and moisture-free basis), increase from approximately-180 to as high as 265.

By the term jelly grade of a pectin is meant the ability of a pectin to form a satisfactory jelly .under standardized conditions.

Pectin as supplied commercially is standardized as to its jellifying strength. For example, a pectin which is capable of setting into a Jelly 01 standard strength and resiliency one hundred and sixty times its weight of sugar in standard jelly containing 65% soluble solids, by weight, may be referred to as 160 grade pectin. The variations in grade very wide.

of commercial pectin may be This pectin is handled in commerce on a certain price per unit of -jelly grade for a unit weight, that is, 200 grade pectin should sell for double the price of the same weight of 100 grade pectin.

Attention is again called to the fact that after the pectin in a pectin'sol has been retarded, by further treatment with the acidic reagent, it may again be speeded up. This is well demonstrated by the samples treated for 5 days and 9 days respectively. The 5 day treatment yielding a pectin setting in 23 minutes, and the 9 day treatment a pectin setting in less than 5 minutes.

Although the foregoing example showed treatment of a pectin sol with acid at room temperature, ithas been found that by increasing the temperature of the acidic pectin sol we will hasten the desired results by cutting down the length of treating time. However, there is a maximum limit above wh ch the temperature should, preferably, not go, namely about 85 C. A preferred temperature would be in the range of 40-60 C.

Likewise it has been found that the more drastic the treatment, the shorter will be the time necessary for such a treatment. More specifically, a pectin sol treated with an acid at a pH of 0.1 will take a much shorter treating time than a sol treated at a pH of 1.8. The above figures are not meant to be maximum and minimum limits for the pH, however, since pH is a factor which is variable and may be adjusted to suit theplant operations, or so adjusted that the maximum setting time retardation will be accomplished in the shortest possible time and at the least expense, and with the greatest gain in jelly grade. The use of too high a concentration of acid, however, should be avoided, as some degradation of the pectin-might take place, along with loss of Jelly strength. Nevertheless, the use of too low a concentration of acid denoted by a pH of approximately 2.5 entails continuing the storage time for an extremely long period. far beyond any economic or practical limit.

Notwithstanding that the examples given have dealt with purified pectinsdispersed in'acid solu- 4 tions, we want to make it clear that pectin sols direct from the extraction may have the setting characteristics of the pectin changed by increasing the temperature of the extracted pectinsol and letting it stand in the presence of the extraction or added acid. Such an example appears hereinafter.

A pectin solobtained from the extraction of citrus pulp with HCl at .a pH of approximately 1.6 was stored at a temperature of 4050 C. for 164 hours. The concentration of pectin in this sol was about 1%. As is shown in Table II, the time of set was retarded from 48 seconds to 455 seconds, over a period of '148 hours. It is also apparent that the jelly grade increased from 1'18 to 185. Although Table It does not show definitely the effects of continued storage longer than 164 hours, yet it does indicate that the setting time is speeding up and the jelly grade decreasing.

TABLE II Sto Setting I n time time in e hours seconds grad" Seconds At a higher pH, namely, 1.6, theset retardation proceeds more slowly for agiven time and temperature than it would at a lower pH in the order of 0.5.

The reagent mentioned hereinbefore has been hydrochloric acid; however, other inorganic acids such as phosphoric-acids; nitric, and sulfuric acid will also apply as will organic acids, citric, lactic, etc. Results Similar to those obtained by HCl may be obtained by using chlorine gas, hydrogen chloride, hydrogen sulfide, sulfur trioxide or sulfur dioxide, etc,, will also act to retard the set of pectin in sol form.

We have found that a 1 to 1 /2% pectin sol is the most suitable concentration to deal with, but our process of treating pectin is applicable to concentrations greater than 0% and less than 5%. The upper limit of 5% is mentioned as that limit beyond which production costs 'and trouble in handling, due to the great viscosity of the sols,

. would be too great for the process to be economically feasible.

It is therefore evident, from the descriptions given hereinabove, that a process has been disclosed which permits the manufacturer, or user, or dealer to alter at will the setting time of pectin in sol form.

Although we have stated as a primary object of this disclosure, the change of setting time, still we have made it apparent that there are other advantages, for example, the improvement of jelly grade of the pectin sol. Furthermore, .pectin precipitated from pectin sols so treated, at optimum conditions of time, pH, concentration, andtemperature, will have a lower ash content and will be lighter in color.

Although specific materials have been men-v tioned as suitable reagents for the process of this invention, they have been set forth -for the purpose of illustration'only, and the invention is not limited thereto. Any and all changes, modifications, or alterations coming within the scope of the appended claims are to be cons dered em- We claim:

1. A method of treating pectin which comprises contacting pectin in sol form, after substantial separation of the pectin from its source material, with an acidic reagent adapted to mate-- rially alter the intrinsic setting time of the pectin, the pectin being maintained in contact with the reagent for a period of time and at a temperature insufficient to destroy the gelation characteristics of the pectin but sufilcient to materially alter the intrinsic setting time thereof.

2. A method as defined in claim 1 in which the reagent comprises "an acid.

3. A method of treating pectin as defined.- in I contact for atime and at a temperature suificient to materially alter the setting time of the pectin, then separating the pectin from the solution and washing the pectin to diminish residual acidity thereof.

6. A method of increasing the setting time of pectin, comprising contacting the pectin in sol form, after substantial separation of the pectin from its source material with an acidic reagent at a pH below 2.5, and for a time and at a temperature sufilcient to materially increase the setting time of the,pectin. I v 7. A method of converting a previously separated, relatively quick-setting pectin into a relatively slow-setting pectin, which comprises dissolving the pectin to form a pectin sol, subjecting the pectin sol to treatment with an acidic reagent adapted to materially increase the setting time of the pectin, maintaining said treatment for a time and at a temperature insufilcient to destroy the gelation, characteristics of the pectin but suificient to materially increase the setting time thereof, and then reducing the pectin to dry form, thereby recovering a relatively slow-setting pectin.

8. A method of converting a previously separated, relatively quick-setting pectin into a rela-' tively slow-setting pectin, which comprises dis-' solving the pectin to form a pectin sol, subjecting the pectin sol to treatment with an acidic reagent adapted to materially increase the setting time of the pectin, maintaining said treatment for a time and at a temperature insuflicient to destroy the gelation characteristics, of the pectin but sufiicientto materially increase the setting time thereof.

9. A method of treating pectin which comprises substantially separating pectin from its source material, contacting the pectin in sol form with an acidic reagent adapted to materially alter the intrinsic setting time of the peetin, the pectin being maintained in contact with the reagent for a period of time and at a temperature insumcient to destroy the gelatimi characteristicsof the pectin but sufilcient to materially alter the intrinsic setting time thereof.

GORDON MANIEY com. 

